Other than Severance, they don't market the shows and movies at all. There's none of the studio PR push - press tours, advance reviews, marketing integrations, etc -- to get people interested in new shows, and no significant back catalog (i.e. Friends on Peacock, Sopranos on Max, etc.) that would get people in either. It feels like a hobby for Apple, and it's producing good stuff, but someone needs to get serious if they want to be a real player.
Also as others have said, the name is so confusing. I can watch Apple TV+ on my Apple TV device or by using the Apple TV app on my (non-Apple) TV but I do need to go to the Apple TV+ section of the Apple TV app or open the Apple TV+ app on my Apple TV. Now imagine explaining this to my mom and dad.